The Russian president today said he would go ahead with a trip to Iran, despite reports of a possible assassination attempt.

"Of course I am going to Iran," Vladimir Putin told reporters at a joint news conference with the German chancellor, Angela Merkel. "If I always listened to all the various threats and the recommendations of the special services I would never leave home."

Mr Putin will be the first Russian leader to visit Iran since Josef Stalin in 1943. During the visit, starting later today, he will meet his Iranian counterpart, Mahmoud Ahmadinejad, and attend tomorrow's summit of Caspian Sea nations.

Russia's Interfax news agency yesterday cited a single unnamed security source as saying Mr Putin had been warned by his special services of a possible assassination attempt during his time in Tehran.

At today's press conference in Wiesbaden, Germany, Mr Putin reiterated his opposition to further sanctions against Iran and called for peaceful means to resolve the dispute over the country's refusal to stop uranium enrichment.

Russia, which is building Iran's first nuclear plant, has resisted the US push for a third round of sanctions against Iran, saying there is no evidence that it is seeking to build nuclear weapons.

But Russia has hedged its position by delaying completion of the Bushehr plant and urging Iran to comply with international controls on its nuclear programme.

In contrast to Mr Putin, Ms Merkel does back the possibility of stronger sanctions against Iran. In an interview published today, Ms Merkel stressed that diplomacy was the way to solve the standoff with Tehran, but also said further action would be needed if Iran refused to heed UN calls for it to halt uranium enrichment.

"We cannot close our eyes to the dangers," Ms Merkel was quoted as telling the German daily Die Welt. "I believe that we need to solve the problem through diplomacy, but at the same time we must be prepared to enact further sanctions if Iran does not come around."